The present invention relates to a new and improved construction of a turntable for depositing a fiber sliver into a spinning can or canister and comprises a sliver duct and calender rolls arranged after and revolving with the sliver duct.
Turntables of this type are employed on various spinning machines which produce a fiber sliver. The fiber sliver, for the purpose of subsequently processing the same, must be deposited in orderly windings or coils in a spinning can or canister. In this arrangement the precision of the sliver deposition is of great importance, since only optimum sliver deposition insures that the sliver can be again removed properly from the sliver can and thus can be presented to the subsequent processing machine, and that the filling weight of the can, i.e., the sliver quantity which can be deposited in the can, can be chosen optimumly high. To insure this it is impermissible for uncontrolled drafts to occur, neither during sliver deposition into the can nor during the subsequent removal from the can.
Turntables of such type are known which permit positive removal of the fiber sliver from the sliver duct to the turntable exit with simultaneous compression or condensing of the sliver by the action of the calender rolls.
Thus, for instance, in German patent publication No. 2,444,020 and the corresponding U.S. Pat. No. 4,041,574 there is disclosed a turntable or coiling device for depositing fiber slivers into a spinning can wherein a sliver duct is followed by a pair of calender rolls which orbit with the sliver duct and, viewed in the direction of flow of the material, directly precedes a sliver exit opening arranged eccentrically in the turntable. The rotational axes of the rolls of the pair of calender rolls are arranged at right angles to the rotational axis of the turntable. Since such type turntables normally are arranged in a horizontal position above the spinning can they rotate about a vertical axis, and the axes of the calender rolls are arranged in a horizontal plane.
In German petty Pat. No. 7,529,051 and the corresponding French Pat. No. 2,323,619, there is disclosed an arrangement of a deflecting roll dispositioned parallel to the calender rolls which also rotate about axes which are horizontally arranged. With this construction there is intended to achieve easier threading-in of the sliver into the turntable and a more reliable guiding of the fiber sliver which passes therethrough at high speed in comparison to the above-mentioned solution utilizing only two calender rolls.
These known proposals employing horizontally arranged calender rolls are associated with various disadvantages. A first drawback resides in the fact that the fiber sliver emerges in vertical direction from the turntable. However, the fiber sliver is deposited winding upon winding in a horizontal plane, during which process the sliver is deflected at the exit of the turntable in tangential direction against the rotation of the turntable. This sharp 90.degree. deflection during deposition results in undesirable damage to the fiber sliver at the very high sliver speeds coming under consideration, which amount to as much as 1000 meters per minute.
A further shortcoming of the state-of-the-art turntables is seen in that the precision of the sliver deposition is impaired by virtue of the fact that the nip of the calender rolls is always located at least at a distance equal to the radius of the depositing rolls above the lower limiting or boundary surface of the turntable. Since the diameters of these rolls should not be chosen to be too small, by taking into account the lap-up danger in accordance with the relation between the staple length of the fiber material being processed and the roll diameter, the guiding point for the fiber sliver is located several centimeters above the deposition plane. Consequently, the precision of the sliver deposition is placed in doubt. However, some relief can be attained if a guide funnel is provided following the calender rolls, for instance as taught in German patent publication No. 2,444,020. Yet, here the frictional problems caused by the 90.degree. deflection of the fiber sliver in the guide funnel are so great that the utilization of such guide funnel becomes problematic.
Considered from the design standpoint these prior art turntables furthermore are afflicted with the considerable disadvantage that an angle or miter gear arrangement is needed for driving the calender rolls. The drive of the calender rolls is preferably derived from the rotational movement of the turntable. Yet, such gear arrangements are extremely problematic when operating at high speeds due to noise-generation, lubrication, maintenance work which is necessitated by wear and so forth.
Finally, the heretofore known turntables have the limitation that they require a relatively large elevational space due to the horizontal arrangement of the calender rolls and the corresponding drive mechanisms. As a result, the operation of the entire machine is negatively influenced due to the excessively large structural height, or otherwise there is required reduction of the maximum employed sliver can height.